Photographic and etching process and product



PHOTOGRAPHIC AND ETCHING PROCESS AND PRODUCT Filed A112. 28, 1925 Patented Jan. 3, 1.928.

UNITED STATES PATENT OFFICE.

MURRAY C. BEEBE, OF CINCINNATI, OHIO, ASSIGNOR T0 TBE WADSWOBTH WATCH CASE C0., 0F DAYTON, KENTUCKY, A CORPORATION UIP-KENTUCKY.

PHOTOGRAPHIC .LND ETCHING PROCESS AND PRODUCT.

Application tiled August 28, 1925. Serial No. 53,205.

The present invention relates to the production of positives, negatives, etchings, sensitive plates, lithograph c plates, etc.

The primary object is to provide an improved etching process and product. A further object is to provide an improved negative and method of producing the same. A further object is the production of improved lithographfc plates. Other objects of the invention will appear from the description which follows.

According to the present invention, I make use of a novel substratum beneath a lightsensitive coating, that is, a film interposed between the light-sensitive lm and the plate. One purpose of the substratum coating is to facilitate the removal of the portions of the light-sensitive coating which are to be removed from the plate, or surface. This may apply either to the unreacted portions of the light-sensitive coating, as where the plate is being prepared for etching; or, it may apply to reacted portions of the lightsensitive coating, as, for example, Where such reacted portions are to be removed after the completion of the etching.

In the case of a negative, which may be made from glass, or Celluloid, the substratum underlying the reacted portions of the sensitive film serves the purpose of giving greater opacity to the subject, or design.

The substratum preferably comprises a water-soluble dye. The d e should be soluble in alcohol or equiva ent solvents, but

' should not be soluble in the solvents and thinners used in the sensitive coating.

The basic dyes are best suited to the purpose. Among these may be mentioned auramine, brilliant green, magenta (fuchsine), methyl violet B, crystal violet, and new magenta.

Of the foregoing, magenta (fuchsine) is preferred. Other dyes which may be usedr body also a portion of a natural resin or a synthetic resin, or other suitable base. A photographic medium of the character here referred to is disclosed, for example, in Beebe and Murray Patent No. 1,574,357, granted February 23, 1926.

Again, the photographic medium may comprise a synthetic res'n, with or without a sensitizing agent. Instances of lightsensitive coatings, or varnishes composed largely of arti cial resins are disclosed in the patents of Murray C. Beebe, Alexander Murray Vand Harold F. Herlinger, as follows: 1,587,269, granted June 1, 1926; 1,587,270, granted June 1, 1926; 1,587,272, granted .lune 1, 1926.

Other patents and applications might be referred to, but the foregoing will suffice, inasmuch as the present invention contemplates the use of the improved substratum in connection with superposed light-sensitive coatings of any desired composition. The improved substratum has been found particularly useful in connection with lightsensitive varnishes comprising oils, resins, etc., which have incorporated therewith, when necessary, a suitable sensitizing agent, such as a small percentage of a halogen compound. Such halogen compounds as iodoform and metallic halides have been found useful in photographic media of the character here referred to.

In the manufacture of lithographie plates, as, for example, in accordance with the method described in the application of Murray C. Beebe, Harold F. Herlinger and Raymond Swain No. 4103, filed January 22, 1925, the method herein described may be employed, if desired, in producing sensitive areas by a photographic process, which sensitive7 areas may afterwards have applied thereto a coating of highl resistant lacquer which is insoluble in in s, as described, for example, in the application just referred to.

In the application of'the present invention to the etching of watch cases, `for example, the improved substratum may be applied to the surface to be etched. After this film is dried, a film of light-sensitive varnish may be applied. This sensitive lm reacted portion of the sensitive film maybe removed in a developing operation b means of a suitable solvent, and the un erlying portions of the substratum may be Washed off by means of water; the watch part may then be subjected to the action of an etching iiuid; and thereafter, the reacted portions of the sensitive coating may be removed by means of another solvent suited thereto, and the underlyin portions of the substratum may bewashe oli' with water, or, both coatings can be removed with an ,alkaline cleaner.

The use of the dye as a substratum facilitates removal of the sensitive coating either before or after the action of light thereon, and is especially valuable in connection with mat surfaces, enabling clean surfaces to be obtained, the tendency of portions of the varnish to remain as a scum in pits, or depressed portions, of the surface to be largely obviated, the substratum itself being cleanly removed quite readily.

The dye substratum coating should be a thin coating. One may use, for example, about thirty grams of dye in a litre of alcohol as a solvent. It is referred to use as a solvent eth l'alcohol enatured with ten percent buty alcohol. `The butyl alcohol evaporates more slowly than ethyl alcohol.

- Such a solvent is adapted to evaporate, after the application of the film at a slow enough rate to avoid the collection of moisture upon the film. A suitable solution is thirty five grams of dye, preferably magenta, in thirteen hundred grams of alcohol, of which about ten percent is butyl alcohol. This is given as a preferred exam le.

Magenta, sometimes cal ed fuchsine, because it is a red dye, is preferred. It does not permit actinic rays to pass through it. This particular feature is of no importance where the method is applied to the etching of metal. The coating of dye should be coherent and also strongl adherent to the glass, metal, or other sur ace.

As indicated above, the d e is soluble in water, and in alcohol or equlvalent solvents. It should not be soluble in benzol (benzene) or benzine, or the type of solvent which is used for the light-sensitive resin, or varnish; nor should it be soluble in the developing solutions ordinarily used, such as benzine, turpentine, or essential oils.

The fact that the dye is soluble in water does not seem lto be detrimental when a stream of water is used for the final development, apparently because the water cannot soak through the reacted film, and does not seem to undermine it.` It seems that the coating of varnish, or resin, penetrates the dye coating to a certain extent and makes 1t rather more insoluble. Ma-

genta dye and some of the other dyes are light-sensitive to a certain extent, but this uality seems to play only a minor part in t e adaptability of the dyes` to the present purpose.

It may be stated here that if the dye is introduced into the sensitive varnish, as distinguished from applying it as a substratum, it slows up the action o the sensitive coatin under the influence of light. On the ot er hand, if the sensitive varnish coating be first printedk and then di ped in a solution of dye, the subsequent eveloping operation tends to leave scum, particularly on a mat surface. A

If desired, a small percentage of a suitable sensitizer, such as iodoform, may be introduced into the solution of dye before it is applied as a substratum to the surface lwhich is subsequently to receive a sensitive coating of a suitable character to have an image formed therein. For example, one may employ iodoform equivalent to about three percent of the dye solution.

As an example of the resent method, one may take a solution o dye consisting of about thirty grams of dye per liter of alcohol and spread it upon a watch-back, for illustration, by whirlin the watch-case back at about three thousan revolutions per minnute. This produces a film of suitable thickness. The film dries in a few seconds. Thereafter, a coating of sensitive varnish, such, for example, as is described in the Beebe and Murray Patent 1,574,357, mentioned above, is applied, as by means of a whirling operation. Light is then projected upon, or transmitted to, the sensitive coating in accordance with an image, design or character, causing the coating to be selectively transformed, reacted or hardened, in accordance with the light reaching the sensitive film. 'The surface is then subjected to a `developing operation by means of a solvent which will remove or soften the unl reacted portions of the sensitive coating. rThe underlying portions of the dye coating may then be removed by means of a stream of water. The watch part may then be subjected to the etching action of a suitable solution, such as a cyanide solution. An example of a suitab e etching solution for gold and gold alloys is as follows:

Grams.

In the etching operation, the watch art dissolved in water (39 Baume). In this case, no electric'current is required to prevent disintegration.

After the etching operation, a suitable solvent, or varnish remover, is employedA to remove the reacted varnish and substratum. A boiling alkaline solution, such as boiling sodium hydrate solution, is suitable. for the purpose. As stated above, a suitable solvent, or developer, for the unreacted varnish coating is an essential oil, or a. mixture of essential oils. Benzine, turpentine, etc. may be used, followed by a Washing, or rinsing, with water. Y

As indicated above, the dye 'coating should be thin. It should be such that the varnish will penetrate it to a considerable extent, butnot so thin that the varnish Will soak through it and adhere strongly to the underlying metal surface. It the dye coating is too thin, it is rather out the image successfully. On the other hand, if the dye coating is too thick, the reacted portion of the image may be undermined to some extent by the Water which is used in the development. This is to be avoided.

It is obvious from the foregoing that the improvement may be employedY with the etching of Watch cases, or metal surfaces. It may be employed, also, in connection with the making of negatives, or positives, on glass, Celluloid, or the like. In the case of glass negatives, or the-like, it is preferred' to use as the light-sensitive varnish coating a solution of. a furfural-ethyl methyl ketone resin. Such a resin is described in some of the patents of Murray C. Beebe, Alexander Murray and Harold F. Herlinger. One of these patents, No. 1,587,269, may be referred to as setting forth examples illustrating the use of furural resins for photographic purposes. A suitable resin may be produced,

for example, by condensing furfural with ethyl methyl ketone. A solution of such a resin may be employed to produce a sensitive coating. While the urfural resinsare in `themselves quite light-sensitive, a suitable sensitizing agent, such as a halogen sensitizer, in small proportion, may be introduced, if desired. Various sensitive varnis'hes may be used according to the present invention in producing glass negatives and the like, or for etching glass, ferred to use a solution of a resin produced by condensing furfural with methyl ethyl ketone.

Various uses for the improvement will suggest themselves to those skilled in the art, and modiications are contemplated.

The practice of the process is illustrated in the accompanying drawing, in Which- Fig. l shows brokenly a metal plate having applied thereto a substratum of dye and a superposed light-sensitive coating; Fig. 2

diiiicult to developv but it is pre-` been reacted upon bylight and the negative developed.

Referring to Fig. 1, A designates a metal plate; B designates a substratum of d e of the characterI described above; and C esignates a light-sensitive coating of the character described above. The corresponding parts are designated by the same reference characters in Fig. 2.

Referring to Fig. 3, A designates a transparent plate, for example, glass; B designates a substratum of dye; and C designates the reacted coating.

It will be understood that in the illustrations shown in Figs. 2 and 3, the light-sensitive coatings have been -caused to react in accordance with an image, or d-esign, and have been developed; also that in the illustration iven in Fig. 2, the plate has been subjected to an etching operation.

In the drawing, suitable legends have been applied to the parts, but unnecessary limitations are not to be understood therefrom.

The dyes mentioned above are listed bei low, with appropriate symbols (see Farbstoff Tabellen of G. Schultz; Dyes classilied 'by intermediates, as compiled by Shreve) (CHQINH m0110201 1. Auramine: y)

- N CH 'C1 (CHIN Blz 3. Brilliant green:

4. Magenta (fuchsin):

Alo

H: N /YNBLHCI 07k/ 5. New magenta (new luohsin):

l Ha

N NH:

SOlNa SOsNa 6. Aold magenta (acid fuchsia):

v SOaNB o-orri 7. Rhodamine-B The foregoingl detaileddescription has been given for clearness of understanding onlyfjbut;osunnecessary limitations shoul be understood"therefrom,but the appended claims shouldfbe construed as broadly as permissible, in viewof the prior art'.

What I regard as new, and desire to secure by Letters Patent, is:

1. The method of preparing a sensitive surface which comprises ap lying to the surface a solution of a. dye an thus forming a substratum film, said solution consisting of about 35 grams of dye in about 1300 grams of alcohol having a slow-drying constituent,

and then applying a superposed light-sensitive film.

2. The method of preparing a sensitive surface which comprises ap lying to the surface a solution of a dye w 'ch 1s soluble in I water and alcohol, and thus forming a substratum'lm, and then applying to said film a superposed light-sens1t1ve film comprising a varnish, said dye being .insoluble in the solvents and thinners employed in said. varnish.

3. An article of the character set forth, comprising a plate, a substratum dye coating thereon, and a superposed light-sensitive coating comprising a non-aqueous colloid, said dye being insoluble in the solvents and thinners employed in connection with said colloid.

4. An article of the character set forth, comprising a surface, a substratum dye coating and a superposed light-sensitve coating comprising a non-aqueous colloid and a halogen sensitlzer.

5. An article of the character set forth, comprising a transparent plate, a substratum film thereoncomprisin a dye which is soluble in water and in alco 'ol, and a superposed light-sensitive coatin comprising a nonaqueous colloid, said ye being insoluble in the solvents employed in connection with said colloid. l

6. An article of the character set forth, comprising a transparent plate, a dye substratum film thereon and a superposed furfural-ethyl methyl ketone coating adapted to be selectively transformed under the action of light in accordance` with an image, design or character.

7. The method of etching which com- Y prises: flowing upon the surface to be etched a dye solution and thus forming a substratum film, flowing onto said film a light-sensitive film 'comprlsing a non-a ueou's colloid and capable of selective trans ormation under th'e action of light, exposing said lastnamed film to the selective action of light in accordance with an image, 'design or character, removing the unreacted portions of the outer film and the underlying portions of the substratum film, and applying to said surf face an etching agent.

8. The method of etching which comprises: flowing upon the Asurface to be etched a dye solution and thus forming a substratum film, flowing onto said film a light-sensitive film com rising a non-aqueous colloid and capable o selective transformation under the action of light, exposing said lastnamed film to the selective action of light in accordance with an image, design or character, removing the unreacted portions of the outer film and the underlying portions bf the substratum film, and etching said surface in a bath comprising potassium cyanide, potassium chloride, 4potassium ferroc anide and water, an electric current c belng passed through the bath, and the part being etched serving as an anode during the etching operation.

MURRAY C. BEEBE. 

